Why are conservatives (and some others) so bent on treating the atrocities committed on September 11, 2001, as acts of war rather than monstrous crimes? They don't look like acts of war. They were not launched by an aggressor nation with the intention of invading and conquering the United States, or overthrowing the government. Despite the enormity of the crimes, the viability of our society is not at risk in the least. Life has gone on rather normally, even allowing for all the ways politicians have exploited the situation in their quest for power. There just seems no good reason to respond by pretending "America is at war." Indeed, the reasons against this response could fill volumes.
So why the insistence that this is war? I think one big reason is that conservatives are, first and foremost, nationalists, and nothing makes nationalism (a form of collectivism) more real than war. Throw in the doctrine of "American exceptionalism" and you have a rationalization for an open-ended "war on terror" in which the world is the battlefield and civil liberties are a luxury we just can't afford.
The war footing also makes it easier to take attention off U.S. interventionist foreign policy, which has seeded the ground for terrorism directed at Americans. One need not excuse the inexcusable acts of September 11 to see how they fit into the big picture. Every empire was struck by terrorists because terrorism is the only low-cost means of retribution available to those who feel aggrieved by imperialism. Most Americans have no clue about what "their" government has been doing in the Middle East for the last couple of generations. It takes shocking ignorance or willful blindness to regard the United States as a gentle sleeping giant until September 11.
So . . . try the criminals in civilian courts. Meanwhile, bring the troops, the CIA, and the meddling diplomats home so this doesn't happen again.